Rag-engine.



No. 787,543. PATENTED APR. 18, 1905.-

' W. SCHMIDT.

RAG ENGINE.

' APPLICATION FILED FEB. 9, 1901- 2 SHEETS-SHEET 1.

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wad W140i mmwwm UNITED STATES latented April 18, 1905.

W ILHELM SCHMIDT, OF LAMBREOHT, GERMANY.

RAG-ENGINE.

SPECIFICATION forming part of Letters Patent No. 787,543, dated April18, 1905.

Application filed February 9, 1901. Serial No. 46,607. 7

1'0 all whom it may concern.-

Be it known that I, W'ILHELM SCHMIDT, manufacturer, residin atKaiserslauterer Staatsstrasse, No. 93, ambrecht, in the Palatinate,Germany, have invented new and useful Improvements in Rag-Engines, (forwhich I have applied for Letters Patent in Germany, Sch. 16,633. VII 55,dated -December 8, 1900; in France, No. 294,948, dated December 22,1900; in England, No. 22,963, dated December 15, 1900; in Russia, No.12,894, dated December 19, 1900; in Denmark, No. 1,357, dated December12, 1900; in Finland, application dated December 14, 1900; in Norway,No. 13,305, dated December 13, 1900; in Sweden, No. 2,128, datedDecember 11, 1900, and in Belgium, No. 121,945, dated December 24,1900,) of which the following is a specification.

My invention relates to the grinding-surfaces of rag-engines in which arotary drum or roller cooperates with a bed-plate.

The object of my invention 1s to improve such grinding-surfaces orgrinding elements so as to render them very strong, durable, andefficient.

The invention will be full described hereinafter and the features ofnovelty pointed out in the appended claims.

In order to enable anybody skilled in the art to carry out my invention,I have appended drawings showing the same.

Figure 1 shows a roller provided with stone cutters disposed insocketson the roller-body. Fig. 2 shows a roller providedwith a stone ring onits periphery. Fig. 3 shows a bedplate with cutters of stone.

Referring to Fig. 1, a is the roller-body, made, for instance, ashitherto, of cast-iron. b represents,sckets or slots, preferably ofsomewhat conical shape, disposed at suitable intervals, which socketsare adapted to receive the cutters or knives or groups of cutters c. dis anintermediate layer of wood, cement, or the like between thecast-iron body and the stone cutters, while e is a wedge, of wood,cement, or other suitable material, for clamping the cutters fast in thesockets. The hold in the cutter is further increased by swelling thewood with water and in the case of cement by allowing it to harden. frepresents the grooves or recesses, wedge-shaped in form, which formprojections, the working edge 9 of which is arranged as far as possibleat right angles to the shaft, the opposite ed e 71. being beveled ofi.These grooves there ore when viewed in cross-section have approximatelythe shape of a triangle the apex of which is rounded. This form of thegrooves presents the following advantage over the hitherto employedrectangular U shaped grooves. In the latter only about that half of eachgroove is filled with material which in the new form is fully filledtherewith, the other half in the old form remaining full of air, whichis carried round by the material and which then escapes into thematerial. The use of the new form of the grooves prevents thedisadvantageous formation of scum caused by ,the air carried around.Even the sharpened edges of the stone do not act with such shearingeffect as the metal knives one against the other, so that the stonesthus rub down the material more into its separate fibers anddisintegrate it rather than out it transversely. When the workingsurfaces become blunted, the grooves may be sharpened by their beingdressed again.

Referring now to Fig. 2, instead of the several cutters disposed inslots of the roller-body the latteris surrounded on its periphery by a Iring of stone fastened by suitable means. On

- the outer surface of this ring i grooves or recesses f are cut out inthe same manner as above described, the letter k denoting the deepergrooves corresponding to the intervals between the several cutters ofthe arrangement shown in Fig. 1.

Referring to Fig. 3, there is shown a bedplate provided with cutters ofstones. Zis the frame or box of the bed-platemade, for instance, ofcast-iron. m represents the several cutters of stone, likewise furnishedwith grooves and fastened in the frame or box by cement, wood, or othersuitable material. The stone of the bed-plate is preferably softer thanthat employed for the roller in order that the wear may preferably takeplace on bed-plate, which is more easily replaced. Especially in thecase of the ring form this would be advantageous. It is also to benoticed that rollers provided with stone cutters may, however, beemployed in conjunction with bed-plates or stationary parts of the kindemployed hitherto, and, further, the cutters of the bed-plate, may alsobe made of stone and the rollers made in the manner formerly employed.As is well known, a lar e stone is usually composed of hard and so tparts, so that, for instance, even the French millstones are made up ofseveral small pieces in orderito obtain an even hardness. By this reasonthe cutters, groups of cutters, or rings may be made of several stonescemented or otherwise firmly connected together. Especially in the caseof a ring surrounding the roller-body this ring may consist of a numberof rings dis posed edgewise and cemented together. The improvedarrangement is not expensive, since the existing roller-bodies andbed-plate frames may be further employed. The stone cutters become wornless than metal knives. Furthermore, the replacement of a knife orcutter which may have become damaged is considerably facilitated,especially in the case of the arrangement according to Fig. 1.

The manufacture of rollers and bed-plates provided with cutters of stonehas a considerable advantage for certain kinds of paper such, forinstance, as the paper for photo graphic purposes-over the use of metal,as this paper material does not contain iron, copper, and tin, whichwould entirely prevent the use of the paper for photographic purposeseven if the smallest traces of these substances were present. I preferto employ basaltic lava on account of its being a homogeneously hard andporous stone. The large number of pores provides a rough and efficientgrinding-surface, which is not materially smoothed by wear, for thereason that the stone is porous throughout. It must also be noticed thatthe use of the improved rollers and bed-plates is also suitable forbevel-mills for grinding paper material, the roller and groundwork ofwhich are conical in shape, so as to fit together. The improvedarrangement may also be employed for socalled centrifugal rag-engmes, 1nwhich the rotary grinding-surface, which 1s provlded with grooves, isnot placed on the periphery, but on the ends of the rollers.

For the purpose of protecting the metallic parts of the working bodiesagainst acids and for preventing metal or rust from mixing with thepaper material all free parts are preferably coated with cement or anysuitable material. For this purpose the stones which form the groups ofcutters and which are inserted in the roller preferably extend over theends of the roller, the extension being about a half to one inch. Theseextensions are coated on a level with the end surfaces with theprotecting material. In the case of the ring form of the stone also therings extend over the end of the roller, and the metallic parts arelikewise coated with protecting material. In a similar manner the freeedges of the frame or box of the bed-plate may be coated.

What I claim, and desire to secure by Letters Patent, is the following:

1. A grinding element, comprising a frame having a plurality ofrecesses, a filling forming a lining for each of said recesses, grindingmembers set in said recesses and embraced by the filling, said membersprojecting outwardly from the recesses, and wedges interposed betweenadjacent grinding members at their projectin portions and en aging theend faces of the fi ling and the end face of the frame between adjacentrecesses.

2. A grindin element, comprising a frame having a plurality of recessescontracted at their mouths, a filling forming a lining for each of saidrecesses and made of varying thickness, so that its inner surfaceincloses a space of uniform width, grinding members set in said recessesand embraced by the filling, the side surfaces of a grinding member,within the recess, being substantially par- 1 allel, while theoutwardly-projecting portions of adjoining grinding members have theiradjacent faces disposed at an angle to each other, and wedges interposedbetween said adjacent faces. a

In testimony whereof I have signed my name to this specification in thepresence of two subscribing witnesses.

WILHELM SCHMIDT.

Witnesses l\/IICHAEL ZIMMERMANN, HEINRIGH RINDERROCKE.

